7install is here for some time and was in testing mode. These days they are updating their site and adding new features and better look to their site.
Right now you can make up to $2.00 per install.
Money earning possibilities:

Software developers can bundle SW with their EXE

it is possible to monetize mobile traffic with their SDK

there is plenty of downloadable SW so you can build SW directory and make money from each download

7install is first PPI I saw that has also referral program for advertisers. So if you like to get your SW distributed than go ahead. The payments are sent via paypal, webmoney or bank wire.